Bent Brass

Peter Holmes

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I have a pair of Amal twin air levers, at some time in the past the longer bottom lever has been bent a little, a small bend near the circular part where the cable sits in the groove, and also a little bend on the bulbous end of the lever, the consequence being that the top and bottom levers will not pass each other, what is the preferred method of bending these back to the correct shape, clearly brass can bend without fracturing (once) as this has done so, my concern is if I attempt to simply bend it back will I be left with three pieces of metal?
 

vince998

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Hi Peter,
Annealing is the best bet. Heat to dull red (in a low light environment) and either allow to cool or quench. The quenching doesn´t really effect the hardness, just allows you to handle the part quicker. (Quenching in dilute vinegar (acetic acid) will leave the brass bright and clean)
Don´t try and bend when hot, it´ll probably rip (Brass is a hot short material and doesn´t take kindly to being worked hot.)
Bend a little when cold, re-anneal,bend a little more. Better to anneal once to often than to little. The advantage here is you can anneal the "bend area" alone and so prevent the rest of the lever being deformed
I´m not sure if this is going to work if they are still chromed (or what effect it´ll have on the chrome when bending).
 

clevtrev

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VOC Member
Hi Peter,
Annealing is the best bet. Heat to dull red (in a low light environment) and either allow to cool or quench. The quenching doesn´t really effect the hardness, just allows you to handle the part quicker. (Quenching in dilute vinegar (acetic acid) will leave the brass bright and clean)
Don´t try and bend when hot, it´ll probably rip (Brass is a hot short material and doesn´t take kindly to being worked hot.)
Bend a little when cold, re-anneal,bend a little more. Better to anneal once to often than to little. The advantage here is you can anneal the "bend area" alone and so prevent the rest of the lever being deformed
I´m not sure if this is going to work if they are still chromed (or what effect it´ll have on the chrome when bending).
As the part is cast brass, do NOT go to dull red. It will melt at that temperature.
 

vince998

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VOC Member
As the part is cast brass, do NOT go to dull red. It will melt at that temperature.

Isn´t all brass cast Trev?

Trev is correct, i believe casting brasses have a higher zinc content which sinks the required casting temperature(and i believe Aluminium is added
to form a protective oxide film to keep the molten metal clean and reduce the attack on the die materials.)
The dull red idea probably wont´t work with the chrome on anyway
 
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